1. Field of the Invention
The present invention relates to a refrigerant suction guide structure for a reciprocating compressor, and more particularly, to a refrigerant suction guide structure for a reciprocating compressor in which suction channel is inclined such that the flow resistance of inhaled refrigerant is reduced to increase the amount of inhaled refrigerant and to thus improve efficiency of a compressor.
2. Discussion of the Related Art
In general, a compressor is an apparatus for converting mechanical energy into compression energy of a compressive fluid and is used as a part of a freezing system such as a refrigerator and an air conditioner.
Among compressors, a reciprocating compressor linearly reciprocates an internal piston inside a cylinder to inhale, compress, and discharge a refrigerant gas. A method of driving the piston is divided into a recipro method and a linear method. According to the recipro method, a crankshaft is combined with a rotating motor and a piston is combined with the crankshaft to convert the rotary force of the motor into linear reciprocating motion. According to the linear method, a piston is connected to a mover of a motor that is in linear motion to reciprocate the piston by the linear motion of the motor.
FIG. 1 is a sectional view illustrating an example of such a reciprocating compressor. As illustrated in FIG. 1, according to a conventional reciprocating compressor, a suction pipe SP and a discharge pipe DP are connected to a sealed casing 10. A frame unit 20 is provided inside the casing 10. A reciprocating motor 30 for generating the driving force and a compression unit 40 for compressing refrigerant are fixed to the frame unit 20. The reciprocating motor 30 linearly reciprocates a mover 33 and is connected to a piston 42. The compression unit 40 includes a cylinder 41 fixed to the frame unit 20, the piston 42 including a suction channel inside, a suction valve 43 provided in the leading end of the piston 42 to limit the suction of a refrigerant gas, and a discharge valve assembly 44 provided in the discharge side of the cylinder 41 to limit the discharge of a compression gas while opening and closing a compression space P.
FIG. 2 is a sectional view illustrating the piston of a conventional reciprocating compressor. As illustrated in FIG. 2, the piston 42 includes a piston body 42A in which a first suction channel 47 is formed in a piston motion direction so as to be connected to the gas suction pipe SP of the casing 10 and a piston head 42B in which second suction channels 48 that are opened and closed by the suction valve 43 is formed in the end of the exit side of the first suction channel 47. One or a plurality of second suction channels 48 are formed to have the same diameter in the direction of a shaft.
FIG. 3 is a front view illustrating one end of the piston of the conventional reciprocating compressor and the suction valve. As illustrated in FIG. 3, the inside of the suction valve 43 is partially cut to be two-arm-shaped. One side of the suction valve 43 forms an opening and closing portion 43A for opening and closing the second suction channels 48 of the piston and the central portion of the suction valve 43 forms a fixing portion 43B fixed to the piston by a fastening bolt B.
In the drawing, the reference numeral 21 denotes a front frame, the reference numeral 22 denotes an intermediate frame, the reference numeral 23 denotes a rear frame, the reference numerals 31 and 32 denote external and internal stators, the reference numeral 31 A denotes a winding coil, the reference numeral 33A denotes a magnet frame, the reference numeral 33B denotes a magnet, the reference numeral 45 denotes a discharge cover, the reference numeral 46 denotes a discharge spring, the reference numeral 50 denotes a resonance spring unit, the reference numeral 51 denotes a spring supporting stand, and the reference numerals 52 and 53 denote a front resonance spring and a rear resonance spring.
The above-described conventional reciprocating compressor operates as follows.
When power is applied to the reciprocating compressor 30 to form flux between an external stator 31 and an internal stator 32, a mover 33 in the slit between the external stator 31 and the internal stator 32 moves in the direction of the flux. The mover 33 is continuously reciprocated by the resonance spring unit 50 such that the piston 42 connected to the mover 33 is in a reciprocating motion inside the cylinder 41. Due to the reciprocating motion of the piston 42, the volume of a compression space P changes such that a series of processes of inhaling a refrigerant gas into the compression space to compress the refrigerant gas and then, discharging the refrigerant gas are repeated.
At this time, refrigerant is received to a sealed container through the suction pipe SP and reaches the compression space p through the first suction channel 47 and the second suction channels 48 formed in the piston 42 to be compressed. The suction valve 43 opens and closes the second suction channels 48 by the pressure difference between the suction channels 47 and 48 and the compression space P caused by the motion of the piston 42 such that the refrigerant is inhaled into the compression space P.
However, according to the above-described conventional reciprocating compressor, the suction valve 43 is fixed to the piston 42 by the fastening bolt B such that the opening and closing portion 43A is bent so as to be opened. Therefore, most refrigerant gas is inhaled into the outside of the suction valve that is opened to a relatively large degree. However, since the second suction channels 48 are formed to have the same diameter, due to channel resistance, the refrigerant gas is not smoothly inhaled. Solid lines, dotted lines, and arrows in FIG. 1 denote the flows of the refrigerant in the first and second suction channels 47 and 48. That is, all the air received through the suction channels does not enter the compression space P at the moment where the suction valve 43 is opened and remains in the suction channels such that the efficiency of the compressor deteriorates.